Department of Physics, Bar-Ilan University, Ramat Gan, Israel.
The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
Sci Adv. 2018 Apr 25;4(4):eaar6277. doi: 10.1126/sciadv.aar6277. eCollection 2018 Apr.
In addition to regular sleep/wake cycles, humans and animals exhibit brief arousals from sleep. Although much is known about consolidated sleep and wakefulness, the mechanism that triggers arousals remains enigmatic. Here, we argue that arousals are caused by the intrinsic neuronal noise of wake-promoting neurons. We propose a model that simulates the superposition of the noise from a group of neurons, and show that, occasionally, the superposed noise exceeds the excitability threshold and provokes an arousal. Because neuronal noise decreases with increasing temperature, our model predicts arousal frequency to decrease as well. To test this prediction, we perform experiments on the sleep/wake behavior of zebrafish larvae and find that increasing water temperatures lead to fewer and shorter arousals, as predicted by our analytic derivations and model simulations. Our findings indicate a previously unrecognized neurophysiological mechanism that links sleep arousals with temperature regulation, and may explain the origin of the clinically observed higher risk for sudden infant death syndrome with increased ambient temperature.
除了常规的睡眠/觉醒周期外，人类和动物还会从睡眠中短暂地醒来。尽管人们对睡眠和清醒的机制已经有了很多了解，但触发觉醒的机制仍然是个谜。在这里，我们认为觉醒是由觉醒促进神经元的内在神经元噪声引起的。我们提出了一个模拟一组神经元噪声叠加的模型，并表明，偶尔，叠加的噪声会超过兴奋性阈值并引发觉醒。由于神经元噪声随温度的升高而降低，我们的模型预测觉醒频率也会降低。为了验证这一预测，我们对斑马鱼幼虫的睡眠/觉醒行为进行了实验，结果发现，正如我们的分析推导和模型模拟所预测的那样，水温升高会导致觉醒次数减少和时间缩短。我们的发现表明，一种以前未被认识到的神经生理学机制将睡眠觉醒与体温调节联系起来，这可能解释了临床观察到的环境温度升高与婴儿猝死综合征风险增加之间的关系。
